Coating applicator

ABSTRACT

An applicator apparatus for placing a predetermined amount of material evenly over an uneven surface. The applicator roll has a covering of resilient material. This material has an outer barrier surface and an initial Shore Durometer of 60 or less on the 00 scale. Preferably, it is between 60 and 15 on the 00 scale. The transfer rolls are of hard material. The transfer roll and the applicator roll both rotate in the same direction causing a sliding contact between the rolls.

United States Patent Blickenderfer, Jr. et al.

[111 3,762,366 1 Oct. 2, 1973 COATING APPLICATOR Inventors: Charles Blickenderfer, Jr., Puyallup;

Harold E.-Erickson, Federal Way; Charles C. Clapp, Tacoma, all of Wash.

Assignee: Weyerhaeuser Company, Tacoma,

Wash.

Filed: Jan. 22, 1971 Appl. No.: 108,823

Related US. Application Data Division of Ser. No. 871,710, Nov. 20, 1969, Pat. No. 3,587,153, which is a continuation of Ser. No. 746,694, July 2, 1968, abandoned, which is a continuation of Ser. No. 481,305, Aug. 20, 1965, abandoned.

US. Cl. 118/262 Int. Cl... B05c 1/08 Field of Search 118/262, 258, 259;

References Cited UNITED STATES PATENTS Staude 118/262 2,676,563 4/1954 Montgomery ct al. 118/262 X 2,560,572 7/1951 Haywood ct al. 118/262 X 2,926,628 3/1960 118/262 X 3,155,541 11/1964 118/262 X 3,468,286 9/1969 Nugarus 118/259 X Primary Examiner-John P. Mclntosh Att0rney-Patrick D. Coogan, John M. Crawford, Stuart A. Heller and Bryan C. Ogden [57] ABSTRACT An applicator apparatus for placing a predetermined amount of material evenly over an uneven surface. The applicator roll has a covering of resilient material. This material has an outer barrier surface and an initial Shore Durometer of 60 or less on the 00 scale. Preferably, it is between 60 and 15 on the 00 scale. The transfer rolls are of hard material. The transfer roll and the applicator roll both rotate in the same direction causing a sliding contact between the rolls.

2 Claims, 3 Drawing Figures COATING APPLICATOR CROSS REFERENCE TO RELATED APPLICATIONS This is a division of application Ser. No. 871,710 filed Nov. 20, 1969 now US. Pat. No. 3,587,153 issued June 28, 1971. which is a continuation of application Ser. No. 746,694 filed July 2, 1968, now abandoned, which is a continuation of application Ser. No. 481,305, filed Aug 20, 1965 now abandoned.

BACKGROUND OF THE INVENTION This invention relates to an apparatus for applying adhesives and other materials to surfaces having varying thicknesses and varying surface characteristics, and specifically relates to an apparatus for applying adhesives to wood veneer sheets.

In the manufacture of plywood there are several requirements for the application of an adhesive to a veneer sheet.

The first requirement is that a metered quantity of adhesive be placed on the veneer sheet. The adhesives normally used are costly and any excessive adhesive that is used will result in a higher cost of plywood produced from the veneer.

An excess amount of adhesive on the veneers will also result in longer press times. The veneers are formed into plywood by being formed into unadhered crossed grain laminae and then being placed into a press which holds the veneers together and heats the veneers to set the adhesive and bond the veneers together. An excessive amount of adhesive will require a longer period of heating to activate the adhesive and remove moisture from the liquid adhesive. This also will result in greater costs in the manufacture of plywood.

Another requirement is to apply the adhesive over the entire surface of the veneer. This is difficult because the veneer has a tendency to curl, and also has surface irregularities such as knots which may protrude above its surface. Therefore, it is necessary to have an applicator roll which will conform quickly to the varying surface characteristics of the veneer passing beneath it.

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to provide an apparatus which will place a predetermined amount of material evenly over the entire surface of the object passing beneath it. It is a further object of this invention to provide an apparatus that can place mate rial on the uneven surfaces and upon objects having varying thickness. It is a specific object of this invention to provide an adhesive applicator that will place a predetermined amount of adhesive evenly over the entire surface of a veneer sheet.

These and other objects will become readily apparent upon a reading of the following specification in conjunction with the attached drawings. While the apparatus will be discussed in conjunction with a specific application to veneer, it is obvious that the apparatus has broader application.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of the applicator apparatus including the applicator roll.

FIG. 2 is a side elevational view partially in section showing the apparatus of FIG. 1.

FIG. 3 is a side elevational view partially in section showing the apparatus of FIGS. 1 and 2 modified for use in a conventional adhesive applicator in which both the top and bottom faces of core stock are glued simultaneously as it passes between the two applicator rolls.

DETAILED DESCRIPTION OF THE DRAWINGS The apparatus shown in FIGS. 1 and 2 is used to place adhesive on the upper face of veneer V passing on a conveyor beneath the applicator roll 10. This distance between the conveyor surface and the lower surface of the applicator roll allows the roll to contact the veneer passing beneath it. Usually, the roll would be adjusted to rest on the conveyor if no material is passing beneath it. The applicator roll 10 has a central core 11, preferably of metal, which is covered with a resilient material 12.

The resilient material 12 must be capable of conforming quickly to the surface characteristics of the veneer passing beneath it so that the adhesive on the roll will be applied to substantially all of the veneer sheet passing beneath it. The material 12 must also have an outer barrier surface so that the portion ofthe applicator roll contacting the veneer sheet will have only a predetermined amount of adhesive thereon and will impart only a predetermined amount of adhesive to the surface of the veneer. It has been found that materials having these characteristics have an initial Shore durometer of or less on the 00 scale and usually have a closed cell structure. Materials having'an initial Shore durometer of under 60 on theOO scale are preferred because of their better resiliency. The material most suitable for this application is a flexible, expanded modified polyvinyl chloride closed cell material having an initial Shore durometer of between 15 and 30 on the 00 scale. The material should be at least inches thick.

The material 12 is attached to the core 11 with a cover adhesive 13. The materials of the cover and the core and the material being applied will'determine the cover adhesive to be used. The cover adhesive should be one that is compatible with the materials forming the cover 12 and the core 11 so that the cover can be adhered to the core, and is compatible with the adhesive being applied to the veneer so that it will not be removed or otherwise be rendered nonadhering by the veneer adhesive.

The veneer adhesive isplaced on the veneer by the applicator roll 10. The roll, which has a shaft 14 that is rotatably mounted in bearingsl5, rotates in the same direction as the veneer passing beneath it and at a peripheral speed that is equal to the lineal speed of this veneer. Thus, the covering 12 contacts and presses down on the veneer to conform to the surface of the veneer and place the adhesive on this surface.

The veneer adhesive is spread on the applicator roll 10 by a metering roll 16, one of a pair of metering rolls 16 and 17. Preferably these rolls have a solid metal core which is covered with a hardrubber. However, one or both of the rolls could be entirely of metal. These rolls have shafts l8 and 19 which are rotatably mounted in their respective bearings 20 and 21.

The spreading of the veneer adhesive on the applicator roll 10 by the metering roll 16 is caused by the two rolls rotating in the same direction so that they are moving in opposite directions at their point of contact,

resulting in a sliding contact between the rolls. The metering rolls pick up adhesive as they move downwardly through the adhesive pool 22 or out of the pan 27 and carry a film outwardly from beneath the nip. It is obvious that the pan 27 may also be used in conjunction with the rolls l7 and 17a.

The predetermined amount of adhesive imparted to the veneer will depend upon the viscosity or flowability of the adhesive, and on the spacing between the metering rolls 16 and 17, and the speed of the metering rolls l6 and 17. The applicator roll 10 must fit tight against the metering roll 16 and tight against the veneer on the conveyor to transfer the exact amount of glue required. The viscosity and the spacing will determine the amount of adhesive that will be transferred and the amount that will be recirculated. There is never a total transference of adhesive from the applicator roll to the veneer.

Preferably, the two metering rolls and the applicator roll are driven by the conveyor motor. Occasionally it is necessary to raise the applicator rolls 10 from the conveyor and the air pistons 25 are provided for this purpose. These pistons are also used to provide the necessary downward pressure of psi at the glue line for a good glue transfer to the veneer.

In FIG. 3, the applicator apparatus is used in a conventional glue spreader which places adhesive on both sides of cross-core veneer. In this apparatus, the applicator rolls 10a and 10b have the same construction as applicator roll 10, and the metering rolls 16a and 17a and 16b and 17b have the same construction as metering rolls l6 and 17. The rolls 10a and 10b are tangential when no veneer is passing through. The apparatus performs in the same manner as that shown in FIG. 1 except that the applicator rolls 10a and 10b now perform the double function of applying adhesive to both sides of the veneer V. and of moving the veneer through the apparatus.

While specific details of preferred embodiments have been set forth above, it will be apparent that many changes and modifications may be made therein without departing from the spirit of the invention. It will, therefore, be understood that what is described herein is intended to be illustrative only, and is not intended to limit the scope of the invention.

What is claimed is:

1. In an adhesive applicator apparatus, an applicator roll having a surface formed of a resilient closed cell material having a maximum initial Shore Durometer of 60 on the 00 scale, a pair of metering rolls positioned adjacent each other, one of said metering rolls being positioned adjacent said applicator roll, said metering rolls being of a relatively nonresilient material, and means for driving said adjacent metering roll and said applicator roll in the same direction.

2. In an adhesive applicator apparatus, an applicator roll having a surface formed of a resilient closed cell material having a maximum initial Shore Durometer in the range of 15 through 60 on the 00 scale, a pair of metering rolls positioned adjacent each other, one of said metering rolls being positioned adjacent said applicator roll, said metering rolls being of a relatively nonresilient material, and means for driving said adjacent metering roll and said applicator roll in the same directron. 

1. In an adhesive applicator apparatus, an applicator roll having a surface formed of a resilient closed cell material having a maximum initial Shore Durometer of 60 on the 00 scale, a pair of metering rolls positioned adjacent each other, one of said metering rolls being positioned adjacent said applicator roll, said metering rolls being of a relatively nonresilient material, and means for driving said adjacent metering roll and said applicator roll in the same direction.
 2. In an adhesive applicator apparatus, an applicator roll having a surface formed of a resilient closed cell material having a maximum initial Shore Durometer in the range of 15 through 60 on the 00 scale, a pair of metering rolls positioned adjacent each other, one of said metering rolls being positioned adjacent said applicator roll, said metering rolls being of a relatively nonresilient material, and means for driving said adjacent metering roll and said applicator roll in the same direction. 